Spark-plug.



W. H. FARRELL.

SPARK PLUG.

APPLICATION FILED IAN.25,1915.

Patented June 8, 1915.

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Inventor Afiorney's WILLIAIYLH. FARRELL, OF SOUTH BETHLEHEM, PENNSYLVANIA. v

SPABK-PLUG.

Specification of Letters Patent.-

Application filed January 25,1915. Serial No. 4,359.

To all whom it may concern:

Be it known that I, WILLIAM H. FARRELL, a citizen of the United States, residing at South Bethlehem, in the county of Northampton and State of Pennsylvania, have invented a new and useful Spark-Plug,- of which the following is a specification.

The present invention appertains to spark plugs for internal combustion engines and the like, and aims to provide a novel and improved construction of a spark plug.

1t is the object of this invention, to provide a spark plug comprising such a unique assemblage of the component elements, that the 'e'iiiciency and serviceability of the plug will 'beenhanced, and whereby the objectionable characteristics of common spark plugs will be eliminated or reduced to a minimum.

As a more specific object, the invention aims to provide a spark plug of such construction, that the central conductor may warp or become distorted, due to the heat to which the plug is subjected in use, without the liability of the. impairment of the device,

the insulation or core also being so formed use.

With the foregoing and other objects in View which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter -de" scribed and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made within the scope of what' is claimed without departing from the spirit of the ,in-

vention.

The invention isillustrated'in its preferred embodiment in the accompanying drawing, wherein- Figure l'is alongitudinal central section of the improvedspark plug. Fig. 2 is a coaxial withthe shell 1.

cross section thereof taken on the line 2-2 of Fig. 1.

The present spark plug embodies a tubu-' lar body or shell 1, constructed of suitable metal, and adapted to be threaded into the aperture or opening ofahydrocarbon engine cylinder or the like. The outer end portion 2 ofthe bore of the shell 1 is, of largest diameter, is of uniform diameter, and isv threaded, while the other or lower end portion 3 of the sleeve bore is of smaller diameter, and is tapered from the shoulder 4 between the portions 2 andll, to the lower or inner end of the shell. ledge 4 faces upwardly'or outwardly.

A pair of diametrically opposite angular Patented June s, rats.

The shoulder or or L-shaped electrodes 5 are carried by the lower or lnner end of the shell 1, certa n arms of the electrodes 5 being engaged intothe lower end of the shell 1 at diametrically opposite points, and the other arms projcctmg toward the axis of the shell at vertically or longitudinally spaced points, to provide. the sparking terminals or tips (3. One sparking terminal 6 terminates shortv of the axis of the shell 1, while the other sparking terminal intersects the axis of the shell beyond or below the first mentioned sparking terminal, as clearly ali parent by reference to Fig. 1. I

The core or insulation comprises lower and upper sections or parts 7 and 8, which are constructed of porcelain or other dielectric material. The lower section or part 7 of the core is tapered. downwardly. and fits tightly within the tapered portion 3 of the V sleeve bore, the upper :end of the section or part 7 being flush with the internal shoulder or ledge 4: of the shell. The upper section or part 8 of thecore is tapered upwardly and extends snugly through the tapered bore of a gland orbushing 9 threaded into the upper end portion 2 of the -sleeve bore, whereby when the gland or bushing. 9 is threaded downwardly, it will move the sec-.-.

' tion. or part" 8. of the" core downwardly to proper position, and hold it in place. The sections or vpartss'f and. 8 of the core are in alinement or coaxiahand'are concentric or meeting ends of the parts of the coreare spaced apart whereby the said. sections. or

parts may move toward eachiother or longitudinally relative to one another, ;without danger of. breakage ,'the sections or parts, however, in being seated within the shell The adjacent or and bushing, respectively, will hold them .against excessive separation.

The central conductor of the plug, like the insulation or core, comprises two parts or sections, one being carried by each at the sections or parts of the core. Thus, the conseating upon the upper end of the section or part 7 of the core. The head 13 is provided with an upper rounded socket or recess 1%, and a retaining nut 15 is threaded upon the lower end of the tubular conductor section 10 and bears against the lower end of the core section 7 to clamp the tubular conductor section 10 tightly in place, to prevent its longitudinal movement relative to the core section 7.

A pencil or pin 16, preferably constructed of hard Zinc or an equivalent alloy, is fitted tightly within the bore 12 of the tubular conductor or section 10, and its lower end protrudes to provide the lower sparking terminal oi the conductor, which projects .toward or terminates short of the sparking terminals 6 of the shell 1. It is to be noted in this connection that one of the sparking terminals 6 projects toward the tip of the sparkingterminal of the conductor in the plane of the said tip, while the other sparking terminal 6 is disposed beyond or below said plane and projects across the tip of the s )arking terminal of the conductor, so that both of the sparking terminals 6 are arranged practically the same distance from the tip of the pencil or pin 16, but are arranged at different positions relative thereto, to assure of the proper action of the plug, and to avoid misfiring of the engine. The pencil or pin 16 being constructed of hard zinc or equivalent; material, will reduce the corroding to a minimum, and will also prevent the crustation of the electrodes which would. impair the elliciency of the plug.

The upper section 11 ot the conductor is .in the form of a rod engaged longitudinally or axially through the upper core section 8,

a nut 17 being threaded upon the lower end portion of the section or rod 11 and being seatedwithin a recess 18 provided in the lower end of the core sectionS. The lower end of the section or rod 11 protrudes beyond the nut 17 to provide a finger 19, the tip of which is rounded and fits snugly within the rounded socket or depression 14, of

the head 13. A cap or cup shaped nut 20 is threaded upon the upper end portion of the section or rod 11 of the conductor and engages over the upper end of the core section. 8, while a lock nut 2-1 is threaded upon the rod 11 above the nut 20 to bind the relative parts in place after they have been a L justed.

Vashers 22 of asbestos or other dielectric or non-conducting material, are disposed between the adjacent ends of the core sections 7 and 8 so as to be clamped therebetween and to surround the adjacent or contacting ends of the sections 10 and 11 of the central conductor to prevent the grounding of the central conductor, or the establishment of a cross circuit or shunt between the outer conductor or shell 1, and the central conductor. The washers 22 are preferably seated upon the shoulder 4, and being compressible, will allow the core sections 7 and 8 to move toward one another, so as to relieve the porcelain sections or parts of in-' j urious strains.

The lower end portion of the tubular section 10 of the conductor is preferably provided with an aperture to provide a vent, whereby the carbonizing ot the central cond actor and its sparking terminal or electrode will be minimized.

The present plug eliminates the excessive strains upon the insulating core, which not infrequently has resulted in the breakage of the core in present day spark plugs embodying a one-part core, and having a one-part central conductor engaged therethrough. In the present device, the sections or parts of the core and central conductor may move slightly relative to one another, under the conditions to which the plug is subjected in use, and the ball and socket joint or connection between the sections or parts of the central conductor, provided by the interengaging rounded finger 19 and socket 14; of the conductor sections, will enable the conductor sections to flex or shift laterally slightly relative to one another, to compensate for any longitudinal movement or expansion ot the core and metallic conductor sections, without the liability of the conductor or sections separating.

The pin or electrode'lG, the lower or inner end of which provides the sparking terminal carried by the central conductor, may be adjusted longitudinally within the tubular conductor section 10, to take up for wear, or to adjust the gap between the sparking terminals of the shell and central conductor. As above intimated, the tubular section 10 of the central conductor is fixed rela tive to the lower core section 7, whereas the upper section or rod 11 of the central conductor is adjustable so as to properly cooperate with the upper end or head 18 of the'lower section 10 of the conductor. To adjust the section or rod 11, the upper nuts 20 and 21 are first loosened, and the lower adjusting nut 17 is then screwed to proper 'positionupon the rod or section 11, so that vthe locking or binding nut 21 is tightened to clamp the rod 11, the nuts 17 and 20 being' held against accidental movement. It

will be observed that the upper end portion or head 13 of the section 10, and the nut 17 and lower end portion of the rod or, section 11 are housed Within the asbestos or insulating washers 22 and the lower recess 18 of the upper core section 8.

In order to prevent the carbonizing of the lower portion of the section or member 10, the same is provided with a longitudinal auxiliary bore 23 extending from its'lower end adjacent the pin or electrode 16, whereby the gases may circulate within the auxiliary bore or recess 23 for the said reasons.

What is claimed is:

1. A spark plug embodying a shell, a core comprising a pair of sections secured therein, a central conductor comprising a pair of sections engaged through the core sections, one end of one conductor section having a head bearing against the end of the respective core section, nuts threaded upon the end portions of the other conductor section and bearingv against the respective core section to hold the second mentioned conductorsection at its adjusted position, one endportion of the second men tioned conductor section projecting from the respective nut, the said head\ having a rounded socket receiving the said end portion of the second mentioned. conductor sect1on, and a nut threaded upon the other end portion of the first mentioned conductor section and hearing against the respective core section.

2. A spark plug embodying a shell, an

WILLIAM H. FARRELL.

Witnesses:

CHARLES J. LAENGER, Y GoNs'r. Gowns.

Copies of this patent. may he obtained for five cents each, by addressing the lommissioncr at same.

ashington, D. (2." 

